Went out to winterize the fifth wheel today ,turned the bypass valve to bypass, turned the water inlet connection to winterize . hooked up the short hose to the inlet connection , then into the gallon jug of antifreeze . Went in the fifth wheel ,turned on the pump ,opened up the kitchen faucet got a little water coming out, but not much. Went back out ,and the jug of anti freeze was empty, and I could see where the antifreeze had been running out the water heater ,I had the plug out. So I turned the bypass valve back ,and forth a couple times from normal to bypass , and tried again , same results .This is the second winter I have had the fifth wheel, no issues last year when winterizing. Its a simple task. Turn to bypass ,and turn the water inlet to winterize ,and get after it. My question at this point do those manual bypass valves go bad ,hard to imagine they would, but can't think of another reason its not bypassing the water heater . Any thoughts before I order a new one, and replace ??

A pic of your bypass setup would help. If you only have a single mechanical valve, to change, I'd suspect another one way valve is leaking back into WH.My current, and other RVs have 3 mechanical valves to turn. One previous RV did develop a slight leak through a closed valve over time, allowing a little seepage into WH.Jerry

If your bypass looks like this, it is likely the one way valve at the top red line out that is stuck open, and may need replacing.Jerry

There are 2 types of water heater bypass systems, the 3 valve - 1 each for in, out and bypass between the in and out. A fool proof design. The other is a 1 valve bypass to inlet that then switches flow to bypass and depends on a auto check valve at outlet to close to prevent inflow to the cold water heater tank. Failures are rare of manually operated valves, check valves do need a good slam of pressure to close. Build up your air or pump pressure to maximum before bleeding the water. When pumping the pink be certain all valves are in winterizing position ( CLOSED) Run the pump until it pressurizes the system to cut off, then go- slowly- to each tap nearest to farthest , 2 times around allowing the pump or compressor to rebuild pressure to each tapEdit, I think you pumped a/f too soon, without enough pressure to close the spring operated check valve.

MFL wrote:If your bypass looks like this, it is likely the one way valve at the top red line out that is stuck open, and may need replacing.JerryThanks Its the one valve system, nothing else to turn off or on. I'll just replace the whole valve body it looks to be one unit, nothing to take apart , has water lines going in from both sides ,and the bottom of it . I watched a YouTube on it ,and it appears those fittings do not come off ,although they do have screwed on fitting, but when you buy the replacement it has barbed fitting in all three connections to hook back up the water lines . . Now on mine those lines are put on with a steel crimped band, so it looks like I will have to cut them off ,and splice back together .

SDcampowneroperator wrote:There are 2 types of water heater bypass systems, the 3 valve - 1 each for in, out and bypass between the in and out. A fool proof design. The other is a 1 valve bypass to inlet that then switches flow to bypass and depends on a auto check valve at outlet to close to prevent inflow to the cold water heater tank. Failures are rare of manually operated valves, check valves do need a good slam of pressure to close. Build up your air or pump pressure to maximum before bleeding the water. When pumping the pink be certain all valves are in winterizing position ( CLOSED) Run the pump until it pressurizes the system to cut off, then go- slowly- to each tap nearest to farthest , 2 times around allowing the pump or compressor to rebuild pressure to each tapEdit, I think you pumped a/f too soon, without enough pressure to close the spring operated check valve. Thanks .And I think I blew it , I took off one of the fitting ,and from what I saw as said on my previous post those fittings are not intended to come off that valve comes with a barbed fitting to hook the lines to . What you are saying makes sense although my last two fifth wheels have had the same valve. I must of been extremely lucky on the previous one, because the way I did it today is how I have done it for the past 13 years. 12 years on the previous fifth wheel , and last year on this one. What I will do is try to reconnect that line ,and see if It leaks when I pressurize the system as you have said to see if I can get that bypass valve to work correctly. It will be no fun to try ,and replace that valve where thy have on the back of the convience center, its a bear to get to. I have the basement panels off ,but still with all the water lines its a messy bunch of lines in there .

Water Heater bypass valve. | Good Sam Community

cummins2014
Explorer
Oct 16, 2021
12thgenusa wrote:
SDcampowneroperator wrote:
There are 2 types of water heater bypass systems, the 3 valve - 1 each for in, out and bypass between the in and out. A fool proof design.
The other is a 1 valve bypass to inlet that then switches flow to bypass and depends on a auto check valve at outlet to close to prevent inflow to the cold water heater tank.
Failures are rare of manually operated valves, check valves do need a good slam of pressure to close. Build up your air or pump pressure to maximum before bleeding the water.
When pumping the pink be certain all valves are in winterizing position ( CLOSED) Run the pump until it pressurizes the system to cut off, then go- slowly- to each tap nearest to farthest , 2 times around allowing the pump or compressor to rebuild pressure to each tap

Edit, I think you pumped a/f too soon, without enough pressure to close the spring operated check valve.

The check valve is spring loaded closed (closed is normal position) and does not require water pressure to close it. When there is no demand on the hot water system, water pressure is equal on both sides of the check valve and it remains closed. When a tap is opened, the pressure in the hot water side drops below the water heater tank pressure allowing it to overcome the check valve spring and allowing water to flow.
They generally fail by gunking up with deposits and stick closed. However I am sure they can stick open the same way.

That also makes sense , either way I am going to just replace it . As said in a previous post I have dealt with this same valve in two different fifth wheels for 13 years ,and this is the first problem I have had . Thanks
cummins2014
Explorer
Oct 16, 2021
Another question , what are the thoughts on using shark bite fittings to replace this valve ??
SDcampowneroper
Explorer
Oct 16, 2021
Shark bite fittings work very well. They are spendy, perhaps enough so that you could buy your own pex crimp tool and parts for the same money. Convenience comes with a high price. Look into that
Down the road a buyer of your unit will see the right fix, not a shortcut.
Other posters to my comment were correct I am wrong , about check valves the check valve in this application is to prevent flow so as a normally closed , low pressure would not be a problem.
cummins2014
Explorer
Oct 17, 2021
SDcampowneroperator wrote:
Shark bite fittings work very well. They are spendy, perhaps enough so that you could buy your own pex crimp tool and parts for the same money. Convenience comes with a high price. Look into that
Down the road a buyer of your unit will see the right fix, not a shortcut.
Other posters to my comment were correct I am wrong , about check valves the check valve in this application is to prevent flow so as a normally closed , low pressure would not be a problem.

Thanks again . I ordered the replacement, one day delivery from Amazon, I saw the tool, and the clamps . I agree I’ll go that route , once I know what fittings I’ll need .
alboy
Explorer
Oct 17, 2021
Anderson makes a brass replacement valve that is a whole lot better,but not cheap.
cummins2014
Explorer
Oct 17, 2021
alboy wrote:
Anderson makes a brass replacement valve that is a whole lot better,but not cheap.

Mt fifth wheel has that brass Andersen valve that's the tank fill, winterization , and city hookup, if that's what you are referring too. The problem is in a separate bypass valve for the water heater , that's a Thetford Valve ,which I am replacing.

I know if you are not careful with those Andersen valves under pressure ,and switching them back ,and forth you can blow an O ring. If say I am hooked to city water ,and want to switch that valve to tank fill, its a good idea to shut the water off first relieve the pressure , switch the valve then turn the water back on . Pretty sure there is no problem with that valve, its in the bypass valve .
ACZL
Explorer
Oct 18, 2021
If you haven't torn apart things just yet, how about just replacing the check valve on the hot water tank 1st? It sounds like we have the exact same kind of docking station set up and the only thing I did from last year was just change the ck valve due to my screw up. So when I went to winterize it this year, no probs.

If you want to, PM me.

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